free website stats program Primary leak | Harley Davidson Forums

Primary leak

BKDIII

New Member
Hello All,

New member with a question. My 2005 RK Classic seems to have sprung a leak at the primary. It is collecting near the drain plug, but I don't think that's where it is leaking. Where are the most common leaks developed at after 23,000 or so miles? I'm riding to Laughlin in less than two weeks and won't be able to do much about the leak until after the trip. Figured I would top off the oil before I go. It is a very slow drip.
 
Last edited:
More than likely if it's not the gasket, it's the starter jack shaft seal or the trans shaft seal as a second choice . Each which would require a bit of work to change.
 
Couple of quick questions:

How bad is the leak? Couple of drops over night, or a pretty good puddle everytime you stop?

Have you cleaned it well so that you can determine if the oil is coming from the left or right side of the primary?

If it is coming from the left, snug up the drain plug a quarter turn (did you use teflon tape on the drain plug when reinstalling?).

Snug up the five derby cover (clutch inspection cover) screws or better, replace the quad ring (gasket).

If the leak seems to be from the right side of the primary, is it chain case oil, or does it seem to be tranny oil or engine oil?

If you are getting a "leak" on the right side of the primary, but can not seem to find a source for the leak, do you still have that goofy u-tube shape short piece of hose on the transmission vent? I had that spraying a fine mist of transmission oil on the right side of the primary that I fussed with for weeks until I figure it out. I just got a longer hose and routed it across the top of the tranny to the rear of the starter and over by the over flow hose on the right side of the bike hanging down towards the road.

Anything more than this will probably mean taking stuff off the bike to see where the leak is. Good luck.

TQ
 
Replace the "O" ring on the drain plug. The newer ones have a "O" ring. Older bikes had none and guys would use thread compound or Teflon tape...Good luck...Hope ya have a great trip.
 
Couple of quick questions:

How bad is the leak? Couple of drops over night, or a pretty good puddle everytime you stop?

Have you cleaned it well so that you can determine if the oil is coming from the left or right side of the primary?

If it is coming from the left, snug up the drain plug a quarter turn (did you use teflon tape on the drain plug when reinstalling?).

Snug up the five derby cover (clutch inspection cover) screws or better, replace the quad ring (gasket).

If the leak seems to be from the right side of the primary, is it chain case oil, or does it seem to be tranny oil or engine oil?

If you are getting a "leak" on the right side of the primary, but can not seem to find a source for the leak, do you still have that goofy u-tube shape short piece of hose on the transmission vent? I had that spraying a fine mist of transmission oil on the right side of the primary that I fussed with for weeks until I figure it out. I just got a longer hose and routed it across the top of the tranny to the rear of the starter and over by the over flow hose on the right side of the bike hanging down towards the road.

Anything more than this will probably mean taking stuff off the bike to see where the leak is. Good luck.

TQ

It left a few drops yesterday after a long and hot run here in Orange Co. Wiped it down last night and did not see anything new today.

I did tighten the drain plug, but I noticed it doesn't bottom out, it just keeps turning, but that does not seem to be where the leak is coming from.
All other bolts were tight.
 
I know drain plugs for the primary are cheap. $3.95 @ the HD dealer. I can't see much difference being in different parts of the country. A few cents maybe, but I would question if they say $13.95. :D Better safe than sorry.
 
I know drain plugs for the primary are cheap. $3.95 @ the HD dealer. I can't see much difference being in different parts of the country. A few cents maybe, but I would question if they say $13.95. :D Better safe than sorry.

Replaced the plug and replaced the Syn 3 with F+. Parts guy at the stealer said Syn 3 has been known to leak where other lubricants may not. So far, no leaks after short test run. Thanks to all for input.
 
Back
Top